<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
<!--    <link href="Demo04.css" rel="stylesheet" type="text/css">-->
    <style>
        a{
            color: aqua;
        }
        a:visited{
            color: cadetblue;
        }
        p:hover{
            color: red;
        }
        /*p:active{
            color: white;
        }*/
        p::selection{
            color: coral;
        }
    </style>
    <title>Title</title>
</head>
<body>

<div style="height: 100px;width:400px ;background-color:cadetblue;">
    <p style="line-height: 100px;margin-left: 150px">
        this is a paragef
    </p>
</div>

<h1>this is headline</h1>
<a href="#bottom" style="margin-left: 450px">to bottom</a>
<p>this is p</p>
<p>aaaaaa</p>
<center>
<a style="text-align: center" href="http://www.baidu.com" target="_blank">a link</a>
    <p>aaaaaa</p>
    <p>aaaaaa</p>
    <p>aaaaaa</p>
    <p>aaaaaa</p>
    <p>aaaaaa</p>
    <p>aaaaaa</p><p>aaaaaa</p><p>aaaaaa</p><p>aaaaaa</p><p>aaaaaa</p>
    <p>aaaaaa</p>
    <p>aaaaaa</p>
    <p>aaaaaa</p><p>aaaaaa</p><p>aaaaaa</p><p>aaaaaa</p><p>aaaaaa</p><p>aaaaaa</p>
    <a href="#" id="bottom">to top</a>
    <div class="box">

    </div>

    <p style="font-weight: bold;line-height: 100%;font-size: 20px">ss</p>
    <p style="font-weight: bold;line-height: 100%;font-size: 20px">ss</p>
    <p style="font-weight: bold;line-height: 100px;font-size: 20px">ss</p>
    <p style="font-weight: bold;line-height: 100px;font-size: 20px">ss</p>

</center>
</body>
</html>